Greenhouses are used to provide a sheltered, controlled environment for plant growth. Thus, most preferably, a greenhouse should foster plant life within it by giving shelter, by controlling the reception of solar radiation, by providing controlled ventilation and by reducing nocturnal re-radiation.
It has been found in practice that all these aforementioned characteristics are difficult to achieve in concert in known greenhouse structures which have a fixed canopy or glazing; this is because the reception of required solar radiation by day is not compatible with the need to conserve warmth by night.
Currently, in warm weather, gardeners whitewash or mount shade cloth to the structure to reduce sunlight and cause vents to open or close to exhaust or trap air. In large greenhouse structures, fans are used for ventilation and electro-mechanical rigid sliding roof panels have been proposed. In cold periods warmth is achieved by heating, and insulating materials may be added at night to prevent heat escape. These procedures are imprecise, laborious and may consume excessive energy.
It is an object of the present invention to alleviate, at least in part, these aforementioned disadvantages.